Miniature robots usually have limited functions and mission capabilities due to a small-sized control part. Especially when a miniature robot performs tasks as photographing, communication, simple cleaning or coating etc. Simultaneously during movements. Applications in microtubules, blood vessels, internal organs might be representative examples.
As an example of such a miniature robot, Korean Patent No. 0402920 discloses an endoscopic micro robot including a rotational shaft rotated by a drive motor installed in a body, a plurality of legs driven by a plurality of cams having phase differences around the rotational shaft, and a propelling parts for moving the body.
However, the micro robot of the above patent has a significant drawback as the robot is moved by complex mechanical sub-system configuration which hence obtains a limit for miniaturization.
In order to solve this problem, Korean Patent No. 0950708 discloses a miniature robot, in which a piezo actuator is applied to a robot joint and the miniature robot can be driven by transformating a linear motion of the piezo actuator into a rotary motion.
However, since most of simple mechanisms using the piezo of the conventional miniature robot or other principles have one degree of freedom in the up and down direction or the fore and aft direction, it is not easy to perform accurate motion and behavior control an unstructured path. In addition, since a number of power transmission mechanisms are needed to convert a one-degree-of-freedom motion of the piezo into multi-degrees-of-freedom motion, there is still a problem of a complex driving mechanism.